The invention relates to the operation of an internal combustion engine. More specifically, the invention is a method and device for evaluating and quantifying the running quality of an internal combustion engine in a marine propulsion system such that the running quality of the engine may be optimized.
When initially manufacturing and later operating an internal combustion engine, one important design characteristic which must be optimized in order for the engine to operate smoothly is the timing of the spark plug ignition as related to the position of the piston in the engine cylinder relative to top-dead center. When the engine is properly tuned, the spark ignition in the engine cylinder produces an optimal explosion that results in the engine operating in a very smooth manner at idle speeds. If the spark timing is a few degrees off relative to top dead-center, the internal combustion engine will run rougher, meaning that at idle, the engine speed tends to fluctuate resulting in uneven performance.
Presently, the running quality of an internal combustion engine is determined and set by a technician who physically listens to the audible changes in the engine performance and watches for vibration in the engine at idle. The trained technician adjusts the spark timing until the engine sounds and looks like it is running more smoothly. While this type of engine tuning has proven effective, especially for a technician having many years of experience, it is an imprecise method that is difficult to teach and duplicate.
Therefore, it can be appreciated that a device which quantifies the running quality of an engine and outputs a signal which can be read and optimized would be a desirable innovation in the internal combustion engine field, particularly the marine propulsion field.